Automatic carbon saver



May 8, 1945. c. e. HUNT AUTOMATIC CARBON SAVER Filed 0C1}. 25, 1943" Patented May 8, 1945 UNITED STATES PATENT OFFICE AUTOMATIC CARBON SAXlEl-It Clyde G. Hunt, Tullahoma, Tenn.

Application October 25, 1943, Serial No. 507,652

11 Claims.

This invention relates to motion picture projection and more particularly to the illumination utilized in conjunction therewith.

It is customary in the projection of motion pictures to use carbon arc lamps to supply the light for the projection and in order to show a full reel of film a prescribed length or carbon is required. These carbons are coated with copper. Ordinarily these copper coated carbons are discarded when they are of an unburned length less than the prescribed full length required for showing a complete reel or film. These unburned lengths may be only slightly shorter than necessary for showing a complete reel, thus resulting in undue waste of material. It is therefore desirable to conserve material and to obtain greater service from that used.

It is an object of the'invention to provide ways and means for using incomplete lengths of carbons in an arc lamp of a motion picture projector for projecting a full reel of film without interruption or stopping to change the carbons thus providing a saving in materials.

A further object of the invention is to provide mechanism enabling the use of a plurality of short sections of carbon arc filaments instead of single filaments.

Another object of the invention is to provide mechanism in conjunction with lamps using carbon filaments for holding a carbon in a position of use and one or more additional carbons in a manner to bring them into a position of use, one by one as needed and very quickly without break- 7 ing the arc.

The foregoing and other objects and advantages will become apparent in view 01' the following description taken in conjunction with the drawing, wherein:

Figure 1 is a side elevation illustrating one application of the invention;

Fig. 2, a top plan of the carbon holder and snap arrangement;

Fig. 3, an elevation illustratin the gauge rod and trip lever; and

Fig. 4, a section on line 4-4 01. Fig. 3.

Referring to the drawing wherein like characters of reference indicate similar parts, the in-. vention is an attachment for a conventional motion picture projector comprising a bed l and a movable carriage l I controllable by a handwheel I2 which operates gearing (not shown) in engagement with the racks IS. on the bed of the machine is also mounted reclprocable mechanism carrying a reflector H, the reflector and carbon holder being movable toward and from each other and each carrying. a single carbon. The. carbon carried by the carriage ll reciprocates by a post l5 and above a clinker tray l6 located in a position to catch falling clinkers or burned particles. The carbons are connected to a source of electrical energy so that when energized light is produced. a

The parts previously described are all conventional, however, with the present invention in lieu of a single carbon supported by the transverse carriage l l, means is provided for supporting and utilizing a plurality of fragmentary carbons. This device consists of a body portion I! with a supporting rod or shaft corresponding in diameter to one of the carbons and adapted to be held in the same manner. The body I! has a channel [9 with side flanges or jaws l9 between which is slidably mounted a transverse reciprocating bar 20 mounted for endwise movement transversely of the supporting rod l8 when the latter is clamped in the upper portion of the transverse carriage.

The bar 20 has an enlarged head 2| of a size that will form a stop for the bar so that it cannot move through the jaws of the member H. A spring 24 is tensioned between a pin 22 on the enlarged head of the bar and the bent end of a rod. 23 fastened in the member I! on the opposite side from the pin 22 so that the spring tends to move the pin 22 and bent end of the rod 23 toward each other and thereby tends to move the bar 20 endwise.

On the slidable bar 20 carbon holders are mounted, the carbon holder 26 having a carbon socket 21 and the carbon holder 28 having a carbon socket '29 in which sockets carbons are adapted to be clamped. The rod 20 therefore when moved will carry the carbons with it and the carbon holders are of different lengths so that one short or incomplete length of carbon may be used and the second length brought into play. In other words the carbon holder 28 with its carbon is in operative position when the bar 20 is moved the maximum distance to extend the length of the spring 24 and to maintain it in this-position while the carbon in the holder 28 is being used. A notch 30 is provided in the bar 20 in alignment with the carbon holder 26 and a pair of lugs 3| support on a pivot 32 a latch 33 having a right angular toe portion 33' extending through a hole in one of the jaws of the member I! for location in the notch 30 in the bar 20 for maintaining the bar in'fixed relation with the spring 24 fully extended. In operation the bar is moved or set by hand, with the toe 33 of the latch engaged in the notch 30 where it is held with the spring extended. Movement of the latch handle releases the latch to permit the snap action shifting of the bar 20 carrying with it the carbon holder 26 to bring its carbon into the previous position of the carbon carried by the holder 28. It will therefore be readily apparent that'the carbon holder 28 and its carbon may be used and then the latch operated to snap the carbon holder 26 and its carbon into-position with a snap action.

In order to provide operating means so that the changeover or shift will occur automatically a guide rod and supporting bracket are provided. It consists of legs 35 and 31 and aligned hollow cylindrical guide members which form a support and guide for a trip rod 40 slidable therein. The trip rod is allowed limited endwise movement on account of an abutment sleeve 4| fastened by a set screw to said trip rod ll].

The trip rod and its mounting'are carried by the longer carbon support 28, and when the carbon holder 28 with its carbon is in a position to be used the trip rod 40 is disposed between the fixture button [5 and the latch 33; consequently when the carriage l l progressively moves the carbon carried by the holder 28 along until its major portion is burned, the trip rod 40 engaging the button I5 and the latch 33 will withdraw the latch from the slot 30 in the bar 20 and permit the spring to snap over the carbon holder 26 to bring its carbon into operative position instantly.

With this arrangement short lengths of carbon can be used in lieu of a single long length, and while only two carbon holders are shown movable in substantially a single plane from one position to the other a larger number of carbons may be used travelling from one position to another. When this carbon has been burned down to the predetermined length, the trip rod 40 will abut the guiding and supporting post l5 and be'moved longitudinally to strike the detent 33, the spring 24 will then snap the slidable bar through the channel [9 in the body I1 and this bar will come to rest with the shorter carbon carried by the rod 26 in alignment with the fixed carbon carried by the reflector l4. Since the shorter carbon was sized when the machine was set up and be fore the film was started, it will now pick up the arc and the running of the film can be continned without any adjustment of the fixed carbon or the transverse carriage member ll. As the longer carbon carrying rod 28 is mounted on the slidable bar 20 and the trip rod 40 is carried by this longer carbon carrying red, the action of the spring 24 in moving the latter rod out of alignment with the fixed carbon will obviously move this rod and the trip rod 40 out of alignment with the guiding and supporting post [5 and the trip rod and its supporting members will not interfere with the adjustment of the transverse carriage member I l to feed the shorter carbon.

Obviously, the distance between the guiding and supporting post l5 and the transverse carriage member ll, when the latter is in its outermost position, will not be the same in all makes of picture projection machines. For this reason the trip rod All is made adjustable by being formed of two parts connected by the sleeve member 4|.

The description above of the use of a full length carbon on the carbon carrying rod 28 and a half length carbon on the carbon carrying rod 26 is by way of expediency only so as to avoid any adjustment of the transverse carriage member H when the carbon carried by the rod 28 has been burned down to the predetermined length and is supplanted by the carbon carried by the rod 26. It is often the case that a full length carbon is not suflicient to run a reel of film whereas two full length carbons would be more than enough. If however it be desired to use twofull length carbons, this could be done without any modification at all of my attachment. Also, it is obviously within the scope of my invention to make the two carbon carrying rods 26 and 28 of the same length or to make the rod 26 of greater length than rod 28 if desired and -to run the transverse carriage member H back to initial position before the feeding of the second carbon is started.

It will be obvious to those skilled in the art that various changes may be made in the invention without departing from the spirit thereof and therefore the invention is not -limited by the disclosure but onl as indicated in the appended claims.

What is claimed is:

1. A carbon saver for a motion picture projector comprising a carbon holder including a frame, carbon holding sockets carried by said frame in axially stepped relation, a support for the frame allowing the frame to move between two positions so that the carbon in one carbon holder may be in operative position and after substantial consumption the frame released to permit the carbon in the other carbon holder to be brought into operative position, means urging the frame toward one extreme position, a latch for securing the frame in its other position, and a gauge rod operative to release said latch, the construction and arrangement being such that when the latch is released the frame will snap from one position to the other and move one carbon from operative position and another carbon into operative position. i

2. In a motion picture projector employing a carbon arc lamp and a carbon rod of a prescribed length for the projection of a full reel of film, a frame for supporting a pair of carbons in fixed axially stepped relation, supporting means mounting the frame so that it may move to bring either of said carbons in operative position whereby one may be burned to a definite length and then the other so that continuous light may be obtained, positive means for moving said frame, means for maintaining the frame biased in oneposition, including a latch, and a trip rod for operating the latch to release the frame and permit it to snap to another position.

3. In a motion picture projector employing carbons for supplying light, a member for holding a plurality of said carbons in axially stepped relation, positive means for moving said holding means, latch means for holding said member in one position so that the carbons may be in operative position, resilient means urging said member toward another position so that another carbon may be brought into operative position upon substantial consumption of the preceding carbon, and an actuator for operating said latch means to permit said member to be moved by the resilient means.

4. In a motion picture projector, an axially movable member, a plurality of carbons carried by said movable member in axially stepped relation, positive means for moving said movable member, means for holding said movable member biased in a given position, and automatic means for releasing said movable member to permit it to move to another position, to bring another carbon into use after one has been substantially used.

5. In a motion picture projector employing carbon for the production of light for projection through film and mechanism including a carbon support movable step by step, a second support adapted to be carried by the first, a member movably carried by said support, means tending to maintain said member in a definite position, means for holding it in another position, means for releasing it so that it may move to said definite position, and a plurality of carbons carried by said movable member one of which is operatively disposed in either position of said 'member.

6. A carbon saver for a motion picture projector comprising a carbon holder adapted to be supported in a manner corresponding to that of a single carbon, said carbon holder including a support, a transverse member slidably movable in said support, means biasing said transverse member towards one extreme position, means for holding it in another position, and carbons carried by said transverse member in axially stepped relation one adapted to be located in operative position in either extreme position or the transverse member.

7. A carbon saver for a motion picture projector comprising a carbon holder adapted to be Y supported in a manner corresponding to that of a single carbon, said carbon holder including a support, a transverse member slidably movable on said support, means biasing said transverse member towards one extreme position, means for holding it in another position, carbons carried by said transverse member in axially stepped rela- I tion one adapted to be located in operative position in either extreme position of the transverse member, and a gauge rod for releasing the transverse member to permit it to snap to its other position.

8. A carbon saver for a motion picture projector comprising a carbon holder for supporting a carbon in a definite position of use, a second carbon holder associated with but axially forward of the first, and means for shifting said carbon holders so that when the first carbon is substantially consumed the tip of the second carbon may be brought into osition and both carbons caused to operate substantially without interruption as a single carbon.

9. A carbon saver for a motion picture projec tor, constructed to utilize a plurality of short carbon segments and cause them to operate as a single long carbon-segment, comprising a plurality of carbon holders, means for supporting said holders in stepped relation so that when one carbon is substantially consumed another may be brought into position of use, and means for causing movement of said carbon holders so that When one carbon is consumed another may be brought into position for consumption, said vmeans for causing movement comprising means for biasing said holders, latch means for maintaining said holders in biased position, and a fixed abutment for releasing said latch means upon predetermined axial movement of the carbon being consumed.

10. In a motion picture projector, a fixed carbon holder and a movable carbon holder, means for positively moving said movable carbon holder axially, said movable carbon holder comprising means for holding a plurality of carbons in axially stepped relation, means for swinging one carbon out of position and for swinging another carbon into position so that a plurality of carbons may be consumed substantially Without interruption as a single carbon, and means for causing a change from one carbon holder to another within the limits of axial movement of said movable carbon holder.

11. In a motion picture projector, a fixed carbon holder and. a movable carbon holder, means for positively moving said movable carbon holder axially, said movable carbon holder comprising means for holding a plurality of carbons in axially stepped relation, means for swinging one carbon out of position and for swinging another carbon into position so that a plurality of carbons may be consumed substantially without interruption as a single carbon, and means for causing a change from one carbon holder to another within the limits of axial movement of said movable carbon holder, and comprising a latch and fixed abutment means operable to roduce the change-over upon predetermined axial movement of said movable carbon holder.

CLYDE G. HUNT. 

